Loud speaker



June 16, 1931. c. A. BERGMANN 1,810,337

LOUD SPEAKER Filed March 8, 1930 BY fie Wm A TTORNE y;

Patented: June -l6, 1 931 CARL A.-BERGI1ANN, BROOKLYN, NEW YORK LOUD: srn exnn Application inea March 8,

' The inventionrelates to loudspeakers for radio-receiving apparatus and more particularly to that class comnonly referred to as dynamic speakers. I

I The indicated type of speakers include in their construction an element generally termed a speaker pot which is usually of cylindrical or other predetermined form and is arranged to contain the pole corewhich ico-operates withthe usual voice coil tube and the customary cone-to-eftect sound amplification, and the conventional magnet coil which surrounds the core; In existing constructions it has been. deemed essential toproper and efficient operation to providethe speaker pot with a continuous and uninterrupted peripheralwall'in order to secure the desired magnetic action. Because of this fact it has been necessary to make one of the end walls of such pots as separate, independent units, combined with the cylindrical bodies of .thepots so as to be capable of being removed in order that the magnet coil may be properly insertedinto place. With such an arrangement the opposedlsurfaces of the body and removable Wall of the speaker pot must fit each other very exactly and. accordingly 1 must be machinejd withextreme care and ex- 'actness in order to prevent interference with the magneticflow experienoehas shown however ;that such interference is not entirely eliminatedeven under the mostcareful con- 7 ditions of manufacture and'assembly.

V 'In dynamic speakers of theclass in ques 3 'tion the core is fixed upon theintegral wall of thepot and projects toward an opening in the removable wall in whichthe voice coil tube isaccommodated. Actual practice has developed t-he fact that GiilClBllt sound reproduction and amplication can be produced only if anannular slot or space of exact uniformity throughout is provided between the voice coil tube and the contiguous portion of the speak- GI'EDOlI-u WVith existing constructions it has been difiicult, if not impossible, to provide the necessary axial registry in the drilling of the two end Walls of the p ot to provide the aforesaid annular slot or space of exact uniformity, with the result that defective speakers are created unless the utmost preciuse even for only a comparatively short space throughout its lifeis produced at relatively extreme labor.

s claims.

tion of a dynamic loudspeaker embodying of the pot as will' be morefully set forth 1930. serial No.- 434,196.

sion is observed in the manufacture and as sembly. s

Even, if initially, the result is satisfactory relative changes which may take place in the body and the removable wall ofthe pot, or the 5 meanswhereby the latter is connected with the body, cause disturbance of such satisfactory conditions after the speaker has been in oftime; Obviously the extreme precision 60 wh ch s required to produce even atemporarily el hcient loud speaker increases the.

cost of production and assembly materially.

Theobjectof the invention is'to provlde' a speaker pot of the type referred to inwhich the above objections and others inherent in existingconstructions are avoided and whereby a speaker I pot of maximum eificiency low cost/and without the necessity for any precision and highly gpaid "skilled Other more specific objects will appear from the description hereinafter and the features of novelty will be pointed out in the Inthe accompanying drawingswhich illustrate an exampleof the invention without, defining its limits F ig. 1 is a side elevathe novel features; Fig. 2 is a side View of a speaker pot; Fig. 3 is a central sectional elevation of the speaker pot and Fig. 4 is an end View thereof. I V

The novel speaker pot comprises a hollow .metallic body of'cylindrical or other pre determined form-and consisting of a peripheral wall 5 and opposite end walls 6 and 7. The latter are cast in one piece, with; or other- I wise made as. integral parts of the peripheral wall'fi whichis interrupted or providedwith at least oneopening 8, dimensioned to admit the customary magnetcoil 9 to the, interior a hereinaftemthe oppositeend walls 6 and 7i are provided respectively with apertures 10 and 11, the aperture 10 being dimensioned to receive the screw-threadedstem or other fastening device 12 ofthe customary pole core 13, which stem 12 is arranged to' receive 1 a nut 14 whereby said pole core is securely fixed upon the end wall 6. The pole core 13 projects from said wall (3 into the aperture 11 of the end wall 7 which aperture 11 is dimensioned to form with said core 13 an annular slot 15 of uniform size throughout as shownin Figs. 3 and 4. The customary voice coil tube 16 extends into the annular slot 15 in the well known way and is combined with the conventional cone 17 in the conventional manner. The cone 17 may be supported by means of any usual or customary support which in the illustrated example comprises aframe 18 carried by arms 19 which are secured to the end wall 7 of the pot by means of screws 20.

In practice themagnet coil 9 is inserted through the opening 8 into the interior of V the pot and is shifted into position until its axial opening registers with the tirely apertures 10 and 11. ,The pole core 13 is then inserted through the aperture 11 and the axial opening of the coil 9 and its screwthreaded stein 12 projected through the aperture 10; when this has been accomplished the nut 14 is screwed home upon the stem 12 to firmly fie:

the pole core 13 and the magnet coil 9 in position in the pot. The other elements of the loud speaker are then fastened in place in any convenient and conventional sequence.

Becauseof the fact that the end walls and peripheral wall of the speaker pot are cast in one piece, or otherwise made as integral parts of each other, the speaker pot is enfree from any oints or dividing lines between surfaces'of separate parts which tend to develop interference with the magnetic action of the loud speaker. At the same time because of the resulting fixed relation between the end walls 6 and 7 the apertures 10 and 11 may be in said end walls respectively with "absolute axial registry, with a minimum of efiort and without the necessity for any particular skill. Because of this fact and due to the aforesaidfived relation between the end walls 6 and 7 the pole core 13when secured in place in the "speaker pot will be perfectly centered in the aperture 11 without requiring any special adjustment or skill to bring this about,

with'the result that the annular slot 15 will always beef uniform and exact dimensions throughout its entirety. \Vith the arrangement set forth it is also a comparatively simplemat-terto place the magnet coil9 in proper osition and to otherwise completely assemlile the loud speaker. p

The necessity for any special machining oi contacting parts is reduced to a minimum and 'makes the js'p'eaker pot easy to produce by relatively unskilled labor and consequently reduces the cost of production to a minimum. By making the peripheral and end walls of the speaker pot as integral parts of each other the development of interference with drilled or otherwise produced the efficient magnetic action of the speaker due to relative physical changes in independent elements is also entirely avoided. In other words, the novel construction provides a speaker ot for dynamic loud speakers which is 0 maximum efliciency throughout its life and is capable of being produced and assembled with a minimum of effort and expense.

It will be understood that the construction, dimensions and shape of the speaker pot will be determined by the nature and character of the co-operating parts of the loud speaker for which it is designed but will always be such as to embody the novel features of the invention.

Various changes in the specific form shown and described may be made within the scope of the claims without departing from the spirit of the invention.

I claim:

1. A speaker pot for dynamic loud speakers, comprising a hollow metallic body all parts of which are integral with each other and provided with an opening in its peripheral wall dimensioned to admit a magnet coil to the interior of said body.

2. A speaker pot for dynamic loud speakers, comprising a hollow metallic body consisting of a peripheral wall and opposite end walls cast as integral parts of said peripheral wall, the latter being provided with an opening dimensioned to admit a magnet coil to the interior of said body.

3. A speaker pot for dynamicloud speakers,

comprising a hollow metallic body consisting of a peripheral wall and opposite end means for securing-a pole core to the one en wall, and the other aperture being dimensioned to form, with said core, an annular slot of uniform size throughout.

In testimony whereof I have hereunto set my hand.

CARL A. BERGMANN.

ICU

ERG 

